Over the years, a number of toy vehicles have been developed to propel a small child across the floor or ground under electric power. Such vehicles employ various drive systems, the simplest of which consists of a battery, an on-off switch, and a single direct-current drive motor for turning one of the vehicle's wheels. In such a system, the vehicle operates only at a single speed, and only in a forward direction. More complex drive systems offer multiple (or variable) speeds, operate more than one wheel, and may offer both forward and reverse drive. An example of such a system is found in U.S. Pat. No. 4,639,646, which describes a two pedal, three-way control for a child's riding toy. The disclosure of that patent is incorporated herein by this reference.
The drive system described in U.S. Pat. No. 4,639,646 includes two rechargeable batteries, two drive motors (one on each rear drive wheel), an on-off switch, and a forward-reverse selector switch. Two-speed operation is provided by selectively connecting the two batteries in either series or parallel configuration. In series, the batteries supply "full" voltage to the drive system, resulting in "high" speed operation. In parallel, the batteries supply "half" voltage to the drive system, resulting in "low" speed operation. The system thus provides an effective way of producing multiple speeds in a toy vehicle without the use of energy-wasting variable resistors or expensive pulse-width-modulation speed control.
One disadvantage of the aforementioned drive system, however, is the need to carry two batteries on the vehicle in order to provide two-speed operation. Another problem relates to the complex electrical wiring arrangement which has heretofore been employed in order to provide reversible, two-speed operation. The latter problem is particularly troublesome in view of the multiple switches required where reverse operation of the vehicle is to be limited to low speed.
It would be desirable to provide an electrical drive system for a child's riding toy which uses a single battery, but which allows for two-speed operation of the vehicle by selecting between alternative wiring configurations of other discrete elements of the drive system, namely, the drive motors. A single battery, it will be appreciated, is less expensive to produce and replace than are multiple batteries, and requires less wiring to connect.
To further reduce wiring, it would be desirable to provide a multi-position electrical switch capable of independently connecting a power source to a plurality of motors in selected alternative configurations. Specifically, it would be advantageous to provide a single multi-position electrical switch capable of: connecting the motors in parallel across the power source in a forward polarity arrangement; connecting the motors in series across the power source in a forward polarity arrangement; and connecting the motors in series across the power source in a reverse polarity arrangement.
Furthermore, it would desirable to provide a multi-position switch in the form of a shift lever capable of placing the toy in either a high-speed forward, low-speed forward, or low-speed reverse configuration. Such switch would most beneficially be arranged to provide for direct connection to the power source and drive motors, with reconfiguration of the circuit being accomplished internally of the switch.